This invention relates to vehicle steering systems, and in particular, to a universal joint for use in tilt steering mechanisms.
Vehicle steering systems having tilt steering mechanisms are commonly used in both land and water vehicles. For example, in a land vehicle such as an automobile, a driver may tilt the steering wheel to its maximum upward position to facilitate the ingress and egress for the vehicle. The smaller the vehicle, the more convenience that is afforded by the tilt steering mechanism.
Similarly, tilt steering mechanisms for marine vehicles facilitate a driver's ingress and egress to the helm seat. However, the application of a tilt steering mechanism to a marine vehicle presents significant challenges for designers due to the wide spread use of hydraulic steering in such vehicles.
In a typical hydraulic steering arrangement, the steering wheel of the marine vehicle is mechanically coupled to a hydraulic pump. The turning of the steering wheel delivers pressurized oil from one of two pump ports depending on the direction of the turn. The pressurized oil is delivered to one of two ends of a hydraulic cylinder that, in turn, pivots an outboard engine, a rudder or the like.
An example of an improved tilt steering mechanism for marine vehicle is shown in U.S. patent application Ser. No. 08/798,832 filed on Feb. 12, 1997, assigned to the assignee of the present invention, and incorporated herein by reference. In the '832 application, the steering shaft is interconnected to the driving shaft of a hydraulic pump by a universal joint. As is known in the art, the universal joint includes two cross pins that ride in a trunnion block. While universal joints of this type are acceptable in most marine applications, the cost of such universal joints can be significant. Consequently, it is highly desirable to develop a low-cost alternative to prior art universal joints.
Therefore, it is a primary object and feature of the present invention to provide a universal joint which is less expensive to manufacture.
It is a further object and feature of the present invention to provide a universal joint for a tilt steering mechanism which is stronger and less likely to fail in response to large loads.
It is a still further object and feature of the present invention to provide a universal joint for use in a tilt steering mechanism which minimizes the "play" of a steering wheel.
It is a still further object and feature of the present invention to provides universal joint for a tilt steering mechanism which can be easily assembled.
In accordance with the present invention, a universal joint is provided. The universal joint includes a generally cup-shaped yolk having a ball receiving cavity therein. A shaft extends along a longitudinal axis and has first and second ends. A ball is mounted to a first end of the shaft. The ball is receivable within the ball receiving cavity in the yolk. A connection structure is provided for interconnecting the ball and the yolk.
The ball may include a slot extending therethrough along an axis perpendicular to the longitudinal axis of the shaft. An insert is receivable within the slot of the ball. The insert includes a passageway extending therethrough. The connection structure, such as a pin, extends through the passageway in the insert and interconnects the yolk to the shaft, thereby allowing the shaft to be pivotable about the pin.
It is contemplated that the insert be generally disc-shaped and have a predetermined diameter which is less than the width of the slot in the ball.
In order to connect the shaft of the universal joint to a steering wheel, the second end of the shaft may be threaded. Further, the base of the yolk may include a key receiving slot therein for receiving the keyed end of the driving shaft of the hydraulic pump.
In accordance with a still further aspect of the present invention, a universal joint is provided having a generally cup-shaped yolk. The cup-shaped yolk includes a base and a generally cylindrical wall projecting therefrom. The wall partially defines a cavity therein. A shaft extends along a longitudinal axis and has a ball at a first end thereof. The ball is receivable in the cavity of the yolk. Mounting structure is provided for pivotably supporting the ball in the cavity of the yolk.
The ball may include a slot extending therethrough for receiving an insert therein. The mounting structure includes a pin which extends through a passageway in the insert so as to interconnect the cylindrical wall of the yolk to the ball.
In yet a still further aspect of the present invention, a tilt steering mechanism for a vehicle is provided. The tilt steering mechanism includes a driving shaft and a steering wheel interconnected by a universal joint such that rotation of the driving wheel correspondingly rotates the steering shaft. The universal joint includes a yolk defining a cavity therein, and a shaft having a first end pivotably supported within the cavity in the yolk. A locking structure is provided for selectively locking the shaft of the universal joint at a predetermined angle to the driving shaft.
The shaft of the universal joint may include a slot therein in order to accommodate a woodruff key. It is contemplated that the steering wheel include a central hub having a passageway for receiving the shaft of the universal joint therethrough. The passageway is defined by a generally cylindrical inner wall of the central hub. The inner wall of the hub includes a recess therein for receiving a portion of the woodruff key in a conventional manner. The recess communicates with the passageway through the central hub.
It is further contemplated that the first end of the shaft of the universal joint include an enlarged head thereon. The enlarged head including a slot therethrough. An insert is receivable within the slot in the enlarged head of the shaft of the universal joint. The insert includes a passageway therethrough. The shaft of the universal joint is pivotably mounted to the yolk by a pin extending through the yolk and through the passageway in the insert. The insert is generally disc-shaped and has an predetermined diameter approximating the diameter of the enlarged head of the shaft of the universal joint.
Various other features, objects and advantages will be made apparent from the following description taken together with the drawings.